132
MICROCHANNEL HEAT EXCHANGER (MCHX) CON-
DENSER COIL MAINTENANCE AND CLEANING
RECOMMENDATIONS
Routine cleaning of coil surfaces is essential to maintain
proper operation of the unit. Elimination of contamination and
removal of harmful residues will greatly increase the life of the
coil and extend the life of the unit. The following steps should
be taken to clean MCHX condenser coils:
1. Remove any foreign objects or debris attached to the coil
face or trapped within the mounting frame and brackets.
2. Put on personal protective equipment including safety
glasses and/or face shield, waterproof clothing and
gloves. It is recommended to use full coverage clothing.
3. Start high pressure water sprayer and purge any soap or
industrial cleaners from sprayer before cleaning condens-
er coils. Only clean potable water is authorized for clean-
ing condenser coils.
4. Clean condenser face by spraying the coil steady and uni-
formly from top to bottom while directing the spray
straight toward the coil. Do not exceed 900 psig or
30 degree angle. The nozzle must be at least 12 in. from
the coil face. Reduce pressure and use caution to prevent
damage to air centers.
CONDENSATE DRAIN — Check and clean each year at
start of cooling season. In winter, keep drains and traps dry.
FILTERS — Clean or replace at start of each heating and cool-
ing season, or more often if operating conditions require. Refer
to Installation Instructions for type and size.
NOTE: The unit requires industrial grade throwaway filters
capable of withstanding face velocities up to 625 fpm.
OUTDOOR-AIR INLET SCREENS — Clean screens with
steam or hot water and a mild detergent. Do not use disposable
filters in place of screens.
Lubrication
FAN SHAFT BEARINGS — Lubricate bearings at least ev-
ery 6 months with suitable bearing grease. Do not over grease.
Typical lubricants are given below:
*Preferred lubricant because it contains rust and oxidation inhibitors.
CONDENSER AND EVAPORATOR-FAN MOTOR BEAR-
INGS — The condenser and evaporator-fan motors have perma-
nently sealed bearings, so no field lubrication is necessary.
Evaporator Fan Performance Adjustment
(Fig. 44) —
Fan motor pulleys are designed for speed
shown in Physical Data table in unit Installation Instructions
(factory speed setting).
To change fan speeds, change pulleys.
To align fan and motor pulleys:
1. Shut off unit power supply.
2. Loosen fan shaft pulley bushing.
3. Slide fan pulley along fan shaft.
4. Make angular alignment by loosening motor from
mounting plate.
5. Retighten pulley.
6. Return power to the unit.
Evaporator Fan Coupling Assembly —
If the cou-
pling has been removed for other blower assembly component
repair or replacement, it is critical that the coupling be reassem-
bled and aligned correctly to prevent premature failures.
REASSEMBLING THE COUPLING INTO THE UNIT
(Fig. 45)
1. Prior to reassembling the coupling, loosen the 4 bearing
mounting bolts, which secure the 2 bearings on either side
of the coupling. Remove the drive belts.
2. Reassemble the coupling with the bearings loose. This
allows the coupling to find its own self-alignment position.
3. Check the hub-to-shaft fit for close fitting clearances.
Replace hubs if high clearances are determined.
4. Check the key for close-fitted clearances on the sides and
0.015 in. clearance over the top of the key. Replace key if
necessary.
5. Be sure that hub flanges, flex members, spacer, and hard-
ware are clean and free of oil.
6. Place the flanges onto the shafts with the hub facing out-
ward. Do not tighten the set screws at this time.
7. Outside of the unit, assemble the flex members to the cen-
ter drive shaft with 4 bolts and nuts. The flex members
have collars that need to be inserted into the smaller hole
of the drive shaft flange.
8. Assemble the flex member/drive shaft assembly to one of
the shaft flanges, using 2 bolts and nuts. Slide the other
shaft flange towards the assembly and assemble using
2 bolts and nuts. If the shafts are not misaligned, the collar
in the flex member should line up with the shaft flange
holes.
CAUTION
Do not apply any chemical cleaners to MCHX condenser
coils. These cleaners can accelerate corrosion and damage
the coil.
CAUTION
Excessive water pressure will fracture the braze between
air centers and refrigerant tubes.
MANUFACTURER
LUBRICANT
Texaco
Regal AFB-2*
Mobil
Mobilplex EP No. 1
Sunoco
Prestige 42
Texaco
Multifak 2
IMPORTANT: Check to ensure that the unit drive matches
the duct static pressure using Tables 3-26.
Fig. 44 — Evaporator-Fan Alignment
and Adjustment
A48-4036
Summary of Contents for Carrier Weathermaker 48A2
Page 105: ...105 Fig 20 Typical Main Control Box Wiring Schematic 48 50A2 A3 A4 A5 Units...
Page 106: ...106 Fig 21 Typical Auxiliary Control Box Wiring Schematic...
Page 107: ...107 Fig 22 Typical 2 Stage Gas Heat Wiring Schematic Size 060 Units Shown a48 8357...
Page 108: ...108 TO NEXT PAGE Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown A48 7296...
Page 109: ...109 Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown cont A48 8358...
Page 110: ...110 Fig 24 Typical Electric Heat Control Schematic 50 Series Size 060 Units Shown a50 8228...
Page 111: ...111 Fig 25 Typical Power Schematic 48 50A2 A3 A4 A5 060 Unit Shown...
Page 112: ...112 Fig 26 Typical Low Ambient Controls Option Wiring...
Page 113: ...113 Fig 27 Typical Small Chassis Component Location Size 020 035 Units...
Page 114: ...114 Fig 28 Typical Large Chassis Component Locations Size 040 060 Units...
Page 118: ...118 Fig 30 Economizer Control Board ECB1 and VAV Control Board ECB2 A48 7706...
Page 142: ...142 A48 3733 Fig 56 Main Burner Removal...
Page 176: ...176 APPENDIX C VFD INFORMATION cont Fig F Internal Enclosure Fan Replacement A48 7716...
